The solution turns out to be using two constraint options provided by SQL Server.
The first is
PRIMARY KEY, which as the name suggests, forces the specified column to behave as a completely unique index for the table, allowing for rapid searching and queries.
While SQL Server only allows one
PRIMARY KEY constraint assigned to a single table, that
PRIMARY KEY can be defined for more than one column. In a multi-column scenario, individual columns can contain duplicate, non-unique values, but the
PRIMARY KEY constraint ensures that every combination of constrained values will in fact be unique relative to every other combination.
The second piece of the puzzle is the
IDENTITY constraint, which informs SQL Server to auto increment the numeric value within the specified column anytime a new record is
IDENTITY can accept two arguments of the numeric
seed where the values will begin from as well as the
increment, these values are typically not specified with the
IDENTITY constraint and instead are left as defaults (both default to
With this new knowledge at our fingertips, we can rewrite our previous
CREATE TABLE statement by adding our two new constraints.
That’s all there is to it. Now the
id column of our
books table will be automatically incremented upon every
INSERT and the
id field is guaranteed to be a unique value as well.